Puget Sound orca pods lose 3

Experts believe missing adult whales may have died of starvation

Published 10:00 pm, Tuesday, October 17, 2006

Three of the 90 orcas that call Puget Sound home are missing and presumed dead, researchers said Tuesday. At least two had shown signs of starvation.

Although it's fairly common for young orcas to perish, the deaths of three adults in or near their reproductive prime is worrisome, researchers said. It's also much more common for whales to die in the winter, when food is scarce, rather than in the usually abundant summer.

One of the dead, a 12-year-old female known as K-28 and as Raven, leaves behind a still-nursing, 4- month-old calf that is now unlikely to survive, researchers said.

"When you're losing a breeding female at the beginning of the reproductive years, that's very significant," Balcomb-Bartok said. "She could have easily added three to four more calves to the population."

The three whale pods that frequent Puget Sound and the waters around the San Juan Islands have been slowly rebuilding since their numbers were greatly reduced by captures for aquariums in the 1960s and '70s. That practice was banned in 1977.

But two other factors have combined to frustrate rebuilding of the orcas' population: a declining amount of their favorite food, salmon; and the continued buildup of industrial chemicals that affect reproduction and the immune system and are believed to make the orcas hungry and weak.

The first orca to disappear this year was a 20-year-old male known as L71, or Hugo. He was last seen July 15. A picture taken of the whale the day before showed he "was in a very thin condition," equivalent to a person's ribs sticking out, said Rich Osborne, director of The Whale Museum in Friday Harbor.

At 20, Hugo had just entered the height of his reproductive years.

In that respect, "they're just like people," said Ken Balcomb, director of the Center for Whale Research.

On Sept. 2, a 34-year-old mother of three known as L-43 or Jellyroll was spotted for the last time. The orcas headed out to the Pacific Ocean for several weeks. She hasn't been seen since. She also had a calf, although he is 2 years old and is probably weaned.

The third missing orca, Raven, was last spotted Sept. 19. The area behind her blowhole that normally stores fat was depressed, a condition known as "peanut head" that is attributed to a loss of calories.

Reports coming into the Orca Network, which follows the orcas' movements, indicate they are having trouble finding enough salmon, said Susan Berta, the group's vice president.

When salmon are plentiful, the whales tend to travel close together, she said. But this year's sightings revealed the whales as spread out, indicating they were foraging and food supplies are short, she said.

While that happens to some degree every year, it's been more common in 2006, Berta said. Combined with the reports about Raven and Hugo, it adds up to a bad year for salmon hunting, she surmised.

The starvation theory matches the experiences of local salmon fishermen, who have complained that 2006 was a terrible year.

"It's a degree of starvation that is very disturbing," Berta said. "It's a scary thing. How many more are we going to lose over the winter?"

The largest losses the orca population has experienced since researchers started following it closely in 1976 were in 1996-97, when the population dropped by five, to 92; in 1998-99, when four died, reducing their number to 85; and 2000-2001, when four died, leaving the population at 80.

The annual counts are done in the summer. In July, their population had rebuilt to 90, with three calves born over the preceding year.

Researchers believe that up to 200 orcas once swam in local waters. Federal officials who protected the animals under the Endangered Species Act hope to rebuild their numbers to 120.

The lack of salmon and the presence of PCBs -- fire retardants banned as too toxic in the late '70s -- likely has a synergistic effect on the orcas, researchers say.

PCBs' effects in other mammals, such as humans and mice, are well known. They reduce the amount of thyroid hormone, making the organism feel run down. They also interfere with reproduction and attack the immune system, among other effects, said Peter Ross, a researcher with the Canadian Department of Fisheries and Oceans.

Working with the Washington Department of Fish and Wildlife, he has documented levels of PCBs in harbor seals in Puget Sound that show those very effects going on. Yet the orcas' blubber contains 10 times the concentration of PCBs recorded in seals.

"There's no question in my mind that the (Puget Sound) killer whales are at increased risk of infectious diseases (and) energetic anomalies," Ross said. "The resident killer whales are salmon addicts. They're going to be vulnerable to anything that affects the viability of salmon.

"Superimposed on that you've got a very contaminated animal -- one of the most contaminated in the world with PCBs."

When a mammal doesn't get enough food, it burns fat -- and that liberates more PCBs that were once stored in fat, researchers believe. That, in turn, can depress thyroid hormones -- which makes the animal feel hungry and run down.

"It's a vicious circle," said Berta, the orca activist. "Things can get worse and worse."